Hidden in the latest Xbox One system update is a great new feature called Instant Sign-In that lets you specify a user that will automatically sign-in when the system powered on. This is useful for those with multiple users configured, or for those who don't have a Kinect that will automatically sign-in the person sitting in front of the console.
The July system update for Xbox One has rolled out, bringing with it a new Snap mode for Achievements, Snap double-tap, and more. But what I'm most personally interested in is a new feature called Instant Sign-in, which lets you automatically sign into the console using a particular user account when the console powers on.
If you're using Kinect to automatically detect you when you power on Xbox One, you may not want to bother with this feature. But this is a great choice for many people, especially those with multi-console households, non-Kinect-based Xbox Ones, or even in cases where Kinect doesn't correctly "see" you at power-on. I've enabled it on the Xbox One in my office because I always want to be signed in when I turn on the console.
The feature is a bit hidden.
To find it, choose Settings from the Dashboard (or tap the Menu button on the Xbox One controller and then choose Settings). Then, in the main Settings screen, choose Preferences under Console. (You'd think this would be in "Sign-in, security & passkey" or perhaps "Power & startup," but no.)
There's a new Instant sign-in option in the middle "System & App" column that is set to "Nobody" by default. If you select that, you will see a list of all the users that are configured on the console.
Select the user you wish to use. Now, you're good to go, and you'll be signed in each time you power on